OPBP-1

OPBP-1 is a D-peptide identified through phage display screening, molecular docking, and molecular dynamics simulation. It possesses high stability, strong oral bioavailability, and significant antitumor activity. Its mechanism of action involves selectively binding to PD-L1, thereby effectively disrupting the PD-1/PD-L1 interaction. This disruption restores T cell function and downregulates the proportion of myeloid-derived suppressor cells (MDSCs), counteracting immune escape. Therefore, OPBP-1 is a candidate molecule for cancer immunotherapy research.

Method: CHO-K1-hPD-L1 cells were co-cultured with PHA/PMA-pre-activated Jurkat T cells, followed by treatment with OPBP-1 (100 μM) or anti-PD-L1 antibody (10 μg/mL) for 48 hours. The percentage of IL-2-positive cells among CD45⁺ Jurkat T cells was detected by flow cytometry.
Result: OPBP-1 (100 μM) significantly enhanced IL-2 secretion in CD45⁺ Jurkat T cells, showing an effect comparable to that of anti-PD-L1 antibody (10 μg/mL) and stronger than that of the parent peptide H12[1].

Method: BALB/c mice were subcutaneously inoculated with CT26 cells. When the tumor volume reached 40–70 mm³, OPBP-1 (0.2 or 0.5 mg/kg) was intraperitoneally injected once daily for two consecutive weeks, and tumor volume was measured.
Result: OPBP-1 (0.5 mg/kg) significantly inhibited CT26 tumor growth without affecting body weight [1].
Method: CT26 tumor-bearing mice were treated with OPBP-1 (0.5 mg/kg, intraperitoneal injection) for two weeks. Tumor tissues were then collected to prepare single-cell suspensions, and the proportions of CD8⁺ T cells and IFN-γ⁺ CD8⁺ T cells were detected by flow cytometry.
Result: OPBP-1 treatment significantly enhanced the infiltration ratio of CD8⁺ T cells and their IFN-γ secretion function in the tumor tissue [1].

H2O: 4 mg/mL (2.71 mM), Sonication is recommended.